Lifting mechanism



Nov. 22, 1932. D. P. ANDERSON 1,888,612

LIFTING MECHANISM Filed sept. 21, 1951 2 sheets-sheet 1 @j /2' fflzvedor:

j DHV/ P HNDEESO/v, 8

Nov. 22, 1982. D R ANDERSON y 1,888,612

L'IFTING MECHANISM Filed Sept. 21, 18.31 2 sheets-sheet 2 FCQIZ.

/ Warneys.

Patented Nov. 212, 1.931?l UNITED-STATES LIFTING MricHNrsM Applicationined september 21,1931, serial n. 564,181. i 'l This is an invention fora lifting mechanism adapted to operate furnace doors, valves, blastfurnace bells and the like. The inventor intends to provide a mechanismwhich is simple and sturdy, no gears, brakes nor'limit switches beinglnecessary.

Having reference to the accompanying drawings:

Figure 1 is a side elevation of an example of the invention arranged tooperate a re# generative furnace door.

Figure 2 is a top plan of Figure 1.

Figure 3 is an end elevation of Figure V1.

Figure 4 is a cross-section on the line IV-IV of Figure 1. f

In detail the `above show a regenerative furnace door 1 raised andlowered by means of a chain 2 passing over a pulley 3, a liftingmechanism constructed according to the pres- 20 ent invention beingconnected to this chain.

This mechanism comprises a pair of differently sized sheaves .4 and 5commonly mounted on the armature shaft 6 of an electric motor 7 with anendless cable 8 arranged from one of these sheaves to the other in themanner of a differential pulley, forming a horizontal loop 9 and avertical loop 10.

A pulley 11, carried by the free end of the horizontal loop 9, has itshousing connected to the chain 2, and a second pulley 12 is carried bythe free end of the vertical loop 10, this latter pulley having a heavythick-walled housing 13 which substantially counter-balances the door. Apair of chains 14 pass over pulleys 15 to resiliently interconnect thepulleys 1l and 12 through compression springs 16 carried by draw bolts17. Preferably this is adjusted so that the compression springs carrypart of the weight of the door.

Although not shown by the drawings, it is to be assumed that thislifting mechanism is located at the top rear end of a bank of furnaceshaving a number of doors similar to that shown and that there will be alifting '45 mechanism for each door. The cable 8 is of a length whichpermits its vertical loop portion 10 to drop the pulley 12 and housing13 onto a stop 18, which may be the floor or a shelf arrangement, whenVtheV `door 1 is in raised 0 position. When this occurs the cable 8 isslacked sothat'ther'e is not sufficient friction i between it and thesheaves 4 and 5 for. driv-` ing'purpose`vvhereby a safetystoppage oc-`curs when the operator-.fails .to cutoff the motor 7 vwhenthedoor'reaches a fully? raised position. v f 1 Thisoperationisepo'sitive and immediate and works `without the `-aid :of delicate`limit switches or other fragiletparts, such las are usually employedA*in lifting mechanisms.

After this'stoppage'has-occurred the cable 8 will immediately tauten`when. the motor A7 is cut off, due to the drag of the door 1,\.so'thatupon reversal of this motor this door will bey lowered. lNo brakesy areneeded-because the y sa friction lof the door andfits frame willjbeVsuliicient to preventany overrunningi: .The

chains -14 serve toprevent the doorfallingfor the pulleys 11' and'12c'aus'ingdamage should the Cable-Sbreak-in service. They furtherserve as a means for adjusting the tension'ofAthiscable-through'thedrawbolts 17. Y i While a specific example of theinvention has been shown and described in accordance with the patentstatutes, it is not intended to,` limit the scope of the inventionexactly thereto, except as defined inthe appended claims.

2. A lifting mechanism including a pair j of interconnected differentlysized sheaves, an endless `cable arranged from one of said sheaves tothe othervin Vtwo looped portions,

a pulley carried by the free end of one of said looped portions forconnection to the object to be lifted, a weighted pulley carried by thefree end of the other of said looped portions this portion beingvertically ar-` ranged and means for stopping the movement of said lastnamed pulley when said'firstilO' V 2 s Y, Y 1,888,612

named pulley has moved to a predetermined position. Y Y Y 3.Y A liftingmechanism comprising a pair of interconnecteddiferently sized sheaves,an endless'cable arranged from one of said sheaves to the other in twolooped portions, a pulley carried Aby the free end of one of saidloopedeportions for ,connection tothe object to be lifted, a secondpulley weighted to substantially counterbalance said object f andcarried by the other of said looped por-r tions this portionbeingverti'cally arranged,A means for interconnecting said" pulleys, fmeans for stopping the movement of said,V 15 last named pulley when'said drst namedv pulley has moved to a predetermined position and meansfor rotating said sheaves. Y 4. A lifting mechanism comprising a pairofinterconnected differently sized sheaves, an endless cableiarrangedfrom one of said sheaves to the other in'respectively horizontally andvertically looped portions, a .pulley carried by the free ,end ofsaidvhorizontally loopedv portion for connection to the object to belifted, a second pulley c arried by said vertically looped portion andweighted to substantially, counterbalance said object, chainsresilientlyconnected between said pulleys and arranged substantially parallel to Iv fig() the sides'of said looped portions, means for stopping themovement o said second named pulley whenl said `first named pulley' has"moved tol a .l predetermined positionwand g means forrotating saidsheaves.

355' 5 In' testimony whereof, I have hereunto set fmyhand.Y f.

Y. yDAID 'PQANDERSON

